The present invention relates to a gas insulated switchgear system having a single phase reserve bus and more particularly to a system for switching circuit breakers and disconnecting switches so as to feed electric current from one of the three phase main buses to the single phase reserve bus when the one of the three phase main buses is grounded.
In the general gas insulated switchgear system, the Japanese Patents Laid-open Nos. 56-139014/1981 and 58-3505/1983 are cited as examples of such system.
In the Japanese Patents Laid-open No. 56-139014/1981, a gas insulated switchgear system which does not have any reserve bus is shown. So, in this gas insulated switchgear system, there is a problem if one of the three phase main bus is grounded, electric current which flows in all of the three phase main bus breaks down.
In the Japanese Patent Laid-open No. 58-3505/1983, a gas insulated switchgear system which has three phase main buses and three phase reserve buses having feeding bus in each phase is shown, and if on of the three phase main buses is grounded, all of the three phase main buses are switched to the three phase reserve buses. But the three phase reserve buses usually using gas insulated type are very big and expensive.